1. Technical Field
A certain embodiment of the invention relates to a shovel having a turning speed reducer.
2. Description of Related Art
A shovel is provided with a turning drive device which drives an upper turning body so as to turn it. The turning drive device often reduces the power from a power source (a hydraulic motor, an electric motor, or the like) in a turning speed reducer (hereinafter referred to simply as a speed reducer) and turns the upper turning body by increased output torque.
As the speed reducer, in terms of being compact, in terms of a change in reduction ratio being easy, or the like, a planetary gear speed reducer in which a sun gear is used as an input element and a planetary carrier of a planetary gear is used as an output element is frequently used. Further, in order to obtain a predetermined reduction ratio, a multistage speed reducer in which a plurality of planetary gear speed reducers are stacked is also frequently used (refer to the related art).